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Arrow-headed Rattle-box (Crotalaria sagittalis)
Arrow-headed Rattle-box (Crotalaria sagittalis), a State Special Concern plant, is found apparently in dry prairie areas, but habitat requirements are not well-understood; it has also been documented along a sandy lakeshore. Blooming occurs late July through early September; fruiting occurs early August through late September. The optimal identification period for this species is late July through late August.
Synonyms: Crotalaria fruticosa, Crotalaria sagittalis var. blumeriana, Crotalaria sagittalis var. fruticosa, Crotalaria sagittalis var. oblonga
- Distinguishing characteristics: Distinguished from other members of the legume family by its combination of simple leaves and yellow petals.
- Flower characteristics: Yellow pea-like flowers with a large upper petal above, two small lateral petals, and a small keel below.
- Fruit characteristics: Oblong, inflated, 1.5 to 3 cm long seed pods.
- Leaf characteristics: 3 to 8 cm long x 1.5 cm wide, simple (not compound as is typical for the pea family), lance-shaped to linear leaves, hairy on both sides; sessile (attached directly to the stem without a petiole).
- Blooming phenology: late July through early September
- Fruiting phenology: early August through late September
- Optimum time to identify: late July through late August
- Growth form: Forb-erect
- Vegetative reproduction:
- Life cycle: Annual
- Comments: Associated Species: Bouteloua curtipendula, B. hirsuta, Sorghastrum nutans, Polygala verticillata, Ambrosia artemisiifolia, Andropogon gerardii, Euphorbia corollata.
Status and Natural Heritage Inventory documented occurrences in Wisconsin
The table below provides information about the protected status - state and federal - and the rank (S and G Ranks) for Arrow-headed Rattle-box (Crotalaria sagittalis). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where this species has been found to date and is not meant as a range map.
|Federal Status in Wisconsin||none|
|Tracked by NHI||Y|
Habitats and landscapes
The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.
General habitat information
- Habitat description: Found apparently in dry prairie areas, but habitat requirements are not well-understood; it has also been documented along a sandy lakeshore.
- Soils: Dry and sandy soils.
This table lists the natural communities that are associated with Arrow-headed Rattle-box. Scores for natural community associations are: "significant" association (score=3), "moderate association" (score=2) or the species can be present but is only weakly associated with the community (score=1).
This table lists the ecological landscape association scores for Arrow-headed Rattle-box. The scores (3=High, 2=Moderate, 1=Low, 0=None) also correspond to the map.
The Endangered Resources Program has developed avoidance measures and management guidelines for plants on the Natural Heritage Working List. These are a work in progress, and we welcome your suggestions and feedback. Sources used in developing this information can be found here.
These are specific actions designed to avoid "take" (mortality) of this species.
- Avoid known individual plant locations and conduct operations elsewhere when they are least likely to cause damage. Ideally, this would involve frozen, snow-covered ground. However, in areas of the state where frozen conditions are unreliable, very dry soils late in the growing season might be the best available alternative. Consult with a biologist, if needed.
- Avoid broadcast spraying of herbicides; use care with spot spraying.
- Avoid locating landings, staging areas, or access routes in open sandy areas dominated by native grasses.
Management guidelines are additional considerations that may help maintain or enhance habitat for this species
- Maintain and restore open habitat through selective clearing and brushing.
- Avoid disturbance to shorelines and the forest-beach interface.
- Prescribed burns and/or brushing may be beneficial (dependent on local site conditions).
Links to additional Arrow-headed Rattle-box information
Other links related to vascular plants (all exit the DNR website)
- Wisconsin Vascular Plants
- Freckmann Herbarium
- Atlas of Wisconsin Prairie and Savanna Flora - Wisconsin State Herbarium
- USDA - NRCS Plants Database
- USGS Midwestern Wetland Flora - field office guide to plant species
- Cofrin Center for Biodiversity Herbarium
- Intermountain Herbarium Grasses of North America
- Orchids of Wisconsin
Support for Wisconsin's rare plant information has been provided by the Division of Forestry, the Endangered Resources Fund and the Wisconsin Rare Plant Preservation Fund. To donate, visit the Natural Resources Foundation of Wisconsin.